1. Field of the Invention
This invention relates to an electromagnetic switch, more particularly to an electromagnetic switch with a socket, an electromagnetic module, and a contact module that is to be plugged into the socket and the electromagnetic module.
2. Description of the Related Art
FIGS. 1 and 2 illustrate a conventional electromagnetic switch that includes a housing 3, first and second electromagnetic members 5, 6 mounted in the housing 3, a fixed contact member mounted in the housing 3 above the first and second electromagnetic members 5, 6, and a movable contact member 8 mounted in the housing 3 above the fixed contact member. Each of the first and second electromagnetic members 5, 6 includes a coil 51, a yoke 41 disposed below the coil 51, and an armature 61 disposed above the coil 51. The armature 61 of each of the first and second electromagnetic members 5, 6 has a pair of pushing arms 71 extending upwardly therefrom toward and pivoted to the movable contact member 8 via pivot studs 83 which are formed on two opposite ends of the movable contact member 8. First and second urging members 84, 85 are mounted in the housing 3 for respectively urging the opposite ends of the movable contact member 8 in an upward direction. The movable contact member 8 includes first and second movable contacts 821, 822, and is rotatable between a first angular position, in which, the first movable contact 821 is turned downwardly to electrically contact a first fixed contact 311 of the fixed contact member, which results from downward movement of the armature 61 of the first electromagnetic member 5 against an urging action of the first urging member 84 via the yoke 41 of the first electromagnetic member 5 upon actuation of the coil 51 of the first electromagnetic member 5, and a second angular position, in which, the second movable contact 822 is turned downwardly to electrically contact a second fixed contact 312 of the fixed contact member, which results from downward movement of the armature 61 of the second electromagnetic member 6 against an urging action of the second urging member 85 via the yoke 41 of the second electromagnetic member 6 upon actuation of the coil 51 of the second electromagnetic member 6.
The conventional electromagnetic switch is disadvantageous in that since all of the components thereof are mounted in the housing 3, the assembly operation is relatively inconvenient and time-consuming. As a consequence, the manufacturing cost of the conventional electromagnetic switch is significantly increased. Moreover, the repair and the mounting and dismounting of a plurality of conductive wires thereon are laborious, and the urging members 84, 85 tend to fail after a period of use.
Therefore, the object of the present invention is to provide an electromagnetic switch that dispenses with the use of the aforesaid urging members and that is capable of overcoming the aforesaid drawbacks of the prior art.
According to the present invention, there is provided an electromagnetic switch that comprises: an electromagnetic module including a first housing half and first and second electromagnetic members mounted in the first housing half, each of the first and second electromagnetic members including a coil, a yoke, and an armature movable when actuated by the yoke upon application of an electric current to the coil; a contact module including a second housing half connected to the second housing half and having a top wall, the contact module further including a fixed contact member and a movable contact member associated with the electromagnetic module, the fixed contact member being mounted in the second housing half and including conductive first and second fixed contacts and a conductive third fixed contact spaced apart from the first and second fixed contacts, the movable contact member being mounted in the second housing half and including conductive first and second movable contacts which are vertically and respectively aligned with the first and second fixed contacts, and a conductive third movable contact which is electrically connected to the first and second movable contacts and the third fixed contact, the movable contact member being rotatable relative to the fixed contact member among a first angular position, in which the first movable contact is in electrical contact with the first fixed contact, whereas the second movable contact is spaced apart from the second fixed contact when the coil of the first electromagnetic member is actuated, thereby establishing a first circuit passing through the first fixed contact, the first movable contact, the third movable contact, and the third fixed contact, a second angular position, in which the second movable contact is in electrical contact with the second fixed contact, whereas the first movable contact is spaced apart from the first fixed contact when the coil of the second electromagnetic member is actuated, thereby establishing a second circuit passing through the second fixed contact, the second movable contact, the third movable contact, and the third fixed contact, and a normal angular position, in which the first and second movable contacts are spaced apart from the first and second fixed contacts, respectively, when the coils of the first and second electromagnetic members are disabled, each of the first and third fixed contacts having a blade portion extending outwardly through the top wall of the second housing half; and a socket including a socket seat and conductive first and second socket contacts mounted on the socket seat, the socket seat being formed with first and second blade slots for insertion of the blade portions of the first and third fixed contacts and for electrical contact between each of the blade portions and a respective one of the first and second socket contacts.